Engine starter drive



Dec. 10, 1940. Y SEKELLA V 2,224,525

ENGINE STARTER DRIVE Filed Feb. 3, 1938 3 Sheets-Sheet l Dec. 10, 1940.Y. SEKELLA 2,224,525

ENGINE STARTER DRIVE Filed Feb. 3, 1958 a Sheets-Sheet 2 Dec. 10, 1940.SEKELLA 2,224,525

ENGINE STARTER DRIVE Filed Feb. 3, 1938 3 sheets -sheet 3 Patented Dec.10, 1940 hairs!) ST PATENT OFFI ENGINE STARTER DRIVE ApplicationFebruary 3, 1938, Serial No. 188,525

9 Claims. (Cl. 74-7) The present invention relates to engine starterdrives and more particularly to a yielding driving connection for enginestarters.

It is an object of the present invention to provide a starter driveincorporating a novel 'form of self-aifiusting yielding drivingconnection.

It is another object 'toprovide 'sucha device in which the yieldingdriving connection is automatically self-tightening.

It is another object to provide such a device in which the tighteningaction may readily be adapted for various types of yielding couplingmeans.

It is a further object to-provide such a device inwhich the yieldingcoupling means comprises a body of elastically deformable material suchas rubber. I a

It is a further object to provide such a device in which the yieldingcoupling member is in the form of a sleeve, and the control. of thecoupling is obtained bywedging outwardly portiorm of said sleeve.

.It-isn'iiother object to provide such a device in which the yieldingcoupling member is protected from attrition by the expansive memberstherefon.

Further objects and advantages will beapparent from the followingdescription taken in connection with the accompanying drawings in which:

Fig, 1 is a side elevation partiy'in section of a preferred embodimentor the invention;

Fig. 2 is a section taken substantially on the line 22ofFig; =l: I

s Fig. 3 is a perspective detail of certain of the elements of theyielding driving connection illustrated in Fig. 1, shown in disassembledrelation;

Fig. 4 is a view similar to Fig. 1 showing a second embodiment of theinvention;

Fig. 5 is a section taken substantially on the line 5-5 of Fig. 4;

Fig. 6 is a detail partly in section showing a modified form of theembodiment illustrated in Fig.4;

Fig, 7 is a detail view in perspective of certain of the partsillustrated in Fig. 6, shown in disassembled relation;

Fig. 8 is a view similar to Fig. 1, showing a third embodiment of theinvention;

Fig, 9 is an end view thereof and Fig. 10 is a perspective detail ofcertain of the parts illustrated in Fig. 8, shown in disassembledrelation. V

In Fig. 1 of the drawings, there is illustrated a power shaft I whichmay be the extended armature shaft of the starting motor, notillustrated,

carrying a driving member in the form of a pinion 2 slidably androtatably mounted thereon for movement into and out of engagement with amember such as a flywheel gear 3 of an engine to be started. 7,

Means for actuating the pinion 2 from shaft I is provided including ahollow shaft 4 (Fig. 3) having a driving head 5, non-rotatably mountedon shaft I as by means of a pin 6 traversing the driving head and theshaft. 10

A screw shaft I is loosely mounted on the hoilow shaft 4, being retainedthereon by a stop nut 8 threaded on the end of the shaft 4. Screw shaft1 is provided with a driven head 9, and means are provided for rotatingthe driven head 15 from the driving head 5 comprising a barrel member IInon-rotatably connected to the driving head 5 as by means of anomcircular opening l2 in the barrel fitting a projection I3 ofdouble-D" section on the driving head. A cylindrical block 20 II ofelastically deformable material such as rubher is mounted in the barrelI I, and a split sleeve I5 is mounted within the member in frictionalengagement therewith and vnon-rotatably connected tp'the iriverrlieadfi; 25

' Nieansfor expanding the split sleeve I5 to compress the member II inthe barrel and thereby build up the torque capacity of the drivingconnection between the barrel and driven head, is provided in the formof cam projections It on 30 the driven head and a complementaryexpanding member II having cam projections III, which cam projections l6and I8 are adapted to enter tapered slots I9 and 2I respectively in theends of the split sleeve member I5 whereby longitudinal mo- 35 tion ofthe screw shaft I to the left in Fig. 1 causes the cam projections I6and I8 to'expand the split sleeve I5 and compress the rubber block I4.

Means for actuating the pinion 2 from the screw 40 shaft I are providedin the form of a nut 22 normally maintained on a smooth portion 23 ofthe screw shaft I by an anti-drift spring 24, but caused to engage thethreads 25 of the screw shaft by a reentry spring 26. Motion of the nut22 is trans- 45 mitted to the pinion 2 by means of a barrel 2! rigidlyconnected therewith.

In the operation of this embodiment of the invention, rotation of theshaft I is transmitted through the driving head 5-, barrel II and rubberblock I4 to the split sleeve 15, and from thence by means of theprojections I6 to the screw shaft I. It will be understood that the stopnut 8 so positions the screw shaft that the rubber block it ismaintained under some initial compression.

Rotation of the screw shaft causes longitudinal motion of the nut 22thereon until said nut engages the stop nut I, whereby the pinion 2 ismoved into engagement with the enginagear 3. Further rotation of thedrive shaft l transmitted to the screw shaft 1 causes it to threaditself backward to the left in Fig. 1, causing the split sleeve I! to beexpanded by the projections I. and I8, thus compressing the rubber blockuntil sufficient torque is built up to cause the pinion 2 to rotate theengine gear 3.

When the engine starts, the acceleration of the engine gear causes thepinion 2 and its associated parts to overrun the drive shaft, whereuponthe parts are returned to their idle positions.

It may be deemed desirable to increase the adhesion of the rubber blockto the barrel and split sleeve l5 by roughening the surfaces thereof orproviding longitudinal projections or grooves as indicated at 28 and 29.

In the embodiment of the invention illustrated in Figs. 4 and 5, thestructure is substantially similar to the embodiment illustrated inFigs. 1 to 3, but the driving barrel I lid is made removable from thedriving head So without dismounting the drive by the use of a split ringif to retain the barrel, mounted in a groove 32 in the drive head.

In this case, the split sleeve lid is arranged to be expanded by atapered head la on the screw shaft 1a. The sleeve members are formedwith end abutment flanges 33 engaging the end of the barrel Ha, and anexpanslble bushing 34 of elastic sheet material is arranged to enclosethe split sleeve within the rubber coupling block a so as to present acontinuous cylindrical surface to the interior of said coupling member.

The remainder of the structure illustrated in Figs. 4 and 5 is the sameas that illustrated in Figs. 1 and 2, and the operation of the device issubstantially similar.

In Figs. 6 and 7 a modification of the structur illustrated in Figs. 4and 5 is shown in which the split sleeve I5?) is arranged to cooperatedirectly with the interior of the rubber coupling member llb without theinterposition of the expansible sleeve 34 illustrated in Figs. 4 and 5.The remaining structure is the same as illustrated in Figs. 4 and 5.

In Figs. 8, 9 and 10 a third embodiment of the invention is illustratedin which the compressive force applied to the rubber coupling block isboth radial and longitudinal, and is applied at one end only.

In this structure the screw shaft 1c is formed with a tapered head 90adapted to cooperate with a thrust member 35 having a radial flange 36fitting in the end of the barrel I l c and an inwardly tapered portion31 non-rotatably connected with the tapered end So of the screw shaft 10as by means of radial projections 38 on said tapered end extending intoslots 39 formed in the tapered portion 31 of the thrust member.

Longitudinal motion of the screw shaft 10 to the left in Fig. 8 due tothe screw jack action of the screw shaft and nut 220 causes the thrustmember 35 to compress the rubber block llc both radially andlongitudinally until the torque builds up sufiiciently to cause thepinion 20 to rotate the engine gear 30.

The rubber block c is preferably molded with an irregular cross sectionas illustrated in Fig. 8, so as to leave room within the barrel fordlstortion to take place under the compressive action of the member 35,whereby the desired elastic yielding properties of the coupling may besecured.

Although certain embodiments of the invention have been shown anddescribed in detail, it will be understood that other embodiments arepossible and that various changes may be made in the design andproportions of the parts without departing from the spirit of theinvention as defined in the claims appended hereto.

What is claimed is:

1. In an engine starter drive, a power shaft, a pinion movable thereoninto and out of mesh with a gear of the engine to be started. and meansfor actuating the pinion from the shaft including a driving member inthe form of a hollow cylinder, a coupling member therein in the form ofa cylindrical body of elastically deformable material, and load actuatedmeans for wedging said body outward into frictional engagement with theinterior of the driving member.

2. In an engine starter drive, a power shaft, a pinion movable thereoninto and out of mesh with a gear of the engine to be started, and meansfor actuating the pinion from the shaft including a barrel member, acylindrical body of elastically deformable material therein, and torqueresponsive means for wedging a portion .of said body outward intofrictional engagement with the interior of the barrel.

3. In an engine starter drive, a power shaft, 9. driving member movableinto and out of engagement with a member of an engine to be started, andmeans for actuating the driving member from the shaft including a hollowcylinder of elastically deformable material, driving and driventransmission means frictlonally engaging the interior and exterior ofsaid cylinder, and means for moving one of said transmission meansradially to compress the cylinder between said transmission means.

4. In an engine starter drive, a power shaft, a driving member movableinto and out of engagement with a member of an engine to be started, andmeans for actuating the driving member from the shaft including a hollowcylinder of deformable material having a high coefficient of friction,driving and driven transmission means frictlonally engaging the interiorand exterior of said cylinder, and means responsive to the torquetransmitted thereby for moving one of said transmission means radiallyto compress the cylinder between said transmission means.

5. In an engine starter drive, a power shaft, a driving member movableinto and out of engagement with a member of an engine to be started, andmeans for actuating the driving member from the shaft including a hollowcylinder of elastically deformable material having a high coefliclent offriction, inner and outer cylindrical transmission members frictlonallyengaging the interior and exterior of the elastic cylinder respectively,the inner cylinder being longitudinally slotted, and means operated bythe torque transmitted therethrough for moving the inner cylinder toexpand the interior of the elastic cylinder.

6. In an engine starter drive, a power shaft, a pinion movable thereoninto and out of mesh with a gear of an engine to be started, meansactuated by the power shaft for moving the pinion into operativeposition and rotating it to crank the engine including a hollowcylindrical body of elastically deformable material, driving and pinionfor traversing and rotating the pinion, and means whereby the thrust ofthe screw shaft caused by the torque transmitted thereby to the pinionmoves one of said transmission means radially to tighten the frictionalengagement of the transmission means.

"I. In an engine starter drive, a power shaft, a pinion movable thereoninto and out of mesh with a gear of an engine to be. started, meansactuated by the power shaft for moving the pinion into operativeposition and rotating it to crank the engine including a hollowcylindrical .body

of elastically deformable material, transmission means frictionallyengaging the interior and exterior of said body, and a slidable shafthaving a screw-threaded connection to the pinion for traversing androtating the pinion, and having a cam connection with the. interiortransmission means arranged to expand the interior of the elastic bodyresponsive to torque transmitted therethrough.

8. In an engine starter drive, a power shaft, a

a, member adapted to engage and drive a member of an engine to bestarted. and a yielding driving dinally split, and torque-responsivemeans for expanding the split transmission member within the block.

9. In an engine starter drive, a power shaft, a member adapted to engageand drive a member of an engine to be started, and a yielding drivingconnection therebetween including a hollow cylindrical block ofelastically deformable material, inner and outer transmission membersfrictionally engaging the interior and exterior of the block, 'a taperedexpanding member arranged to enter one end of the block, andtorque-responsive means for forcing said expanding member into theinterior of the block.

YOUSTON SEKELLA,

' said inner transmission member being longitu-

